Human immunodeficiency virus (HIV) is a pathogenic retrovirus causing AIDS and its related disorders. The development of antiviral chemotherapy against AIDS has been the subject of an intense research effort since the discovery of HIV. (For a recent review on molecular targets for AIDS therapy see Mitsua et al, Science, 1990, pp 1533-1544). The HIV Proteases (HIV PR), and aspartyl proteases, were first suggested as a potential target for AIDS therapy by Kramer et al. (Science, 231, 1580, 1986). Since that time the potential usefulness of HIV PR inhibitors as effective agents in treatment of AIDS has been widely recognized (for a review of the HIV PR as a therapeutic target see Tomaselli et al. Chimica Oggi, May 1991, pp 6-27 and Huff J. R., J.Med.Chem., 1991, 34, 2314-2327). Of the classical transition state mimics for aspartyl proteases, the hydroxyethylene, dihydroxyethylene, hydroxyethylamine and phosphinic acid isosteres appear to provide the greatest affinity for HIV PR. Many inhibitors of HIV PR have been shown to have an antiviral activity at concentrations in the nanomolar range in the different cell systems and are described as such in the patent literature.